This invention relates generally to the servicing of wells, and more particularly concerns wash-out of sand that tends to collect in sub-surface equipment such as standing valves.
Standing valves are typically connected in series with sub-surface well tubing to cooperate with pumping units landed on such valves. For example, a pumping unit may be traveled downwardly in the tubing to land on a standing valve, and operated in response to pressure fluid supply to the unit, for drawing well production fluid upwardly through the valve. A problem that arises concerns the collection of sand in the standing valve, as a result of upward flow of well production fluid in which the sand is entrained. In the past, the tubing was pulled to retrieve the standing valve for removal of sand; however, this technique is expensive and time consuming. No method or apparatus of which we are aware possesses the unusual advantages in structure, function and results which are now afforded by the present invention, toward overcoming the above described problems.